Length Detection System for Biopsy Device

ABSTRACT

A biopsy device for harvesting tissue samples from a body of a living being, e.g. in percutaneous aspiration biopsy, includes a handle unit, a hollow needle comprised in a disposable unit, which is releasably attached to the handle unit, and a sample-receiving device, which is movable in the hollow needle between two positions. Tissue is severed when the sample-receiving device is in a first one of the positions, and the severed tissue sample is ejected from the sample-receiving device in a second one of the two positions. A control system is provided for controlling movement of the sample-receiving device and for arresting the sample-receiving device in the second position. The distance between the two positions and/or a length of the hollow needle may be detectable in a calibration cycle, which is automatically initiated upon attachment of the disposable unit to the handle unit. The disposable unit may include electronic memory means for communicating with the control system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase of International ApplicationNo. PCT/DK2005/000482, filed Jul. 8, 2005, which claims the benefit ofU.S. Provisional Application No. 60/586,290, filed Jul. 9, 2004, U.S.Provisional Patent Application No. 60/625,127, filed Nov. 5, 2004, andU.S. Provisional Patent Application No. 60/625,128, filed Nov. 5, 2004,each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a biopsy device for harvesting tissuesamples of human or animal bodies. The invention is particularly, butnot exclusively, aimed at percutaneous biopsy, in which it is desirableto gain access to suspect tissue mass in a minimally invasive manner.The invention is particularly concerned with aspects of a control systemcapable of determining a length of a needle of the biopsy device and/ora distance two positions of a sample-receiving device included in thebiopsy device.

BACKGROUND OF THE INVENTION

For diagnostic purposes it may be desirable to obtain a tissue sample ofa human or animal body for in vitro cytological and/or histologicalexamination. Tissue sampling may be performed either as an open or apercutaneous technique. In the open technique, either the entire suspectmass (excisional biopsy) or part of the suspect mass (incisional biopsy)is removed. Access to the lesion as well as removal is generallyobtained with the use of scalpels, and open biopsies are a reliable—ifquite invasive—means of obtaining tissue samples.

In the percutaneous technique, a needle is used to gain access to thesuspect tissue mass in a less invasive fashion. This needle may behollow, permitting the aspiration of single cells and tissue fragmentsinto a lumen by application of a vacuum (aspiration biopsy).Alternatively, larger tissue cores may be harvested by means of a needlecontaining an inner movable trocar with a notch formed to receive tissuecores, and an outer, slidable cannula with a sharpened distal end usedto sever these cores from the surrounding tissue (core needle biopsy).By advancing the inner trocar into a suspect lesion and subsequentlyadvance the outer slidable cannula to cover the notch completely, atissue sample may be severed and held in the notch. The needle may thenbe retracted from the body of the patient, and the tissue sample may becollected and stored for further analysis.

Core needle biopsy devices have been preferred tools among physiciansdue to their simple use and versatility. The core needle devices may beapplied to a broad range of different tissues and different anatomicallocations, and provide the pathologist with samples suitable forhistological analysis for the accurate diagnosing and staging of suspectmasses.

Obtaining the largest possible sample size is an important objective inthe harvesting of core tissue samples. Prior art biopsy systems haveused vacuum to engage and draw tissue towards the notch ortissue-receiving chamber or basket of the biopsy device prior tocutting. Thus, tissue sample sizes may be significantly increased with agiven biopsy needle diameter or larger samples extracted with the sameneedle diameter to improve diagnostic accuracy.

Another well-known prior art technique to increase sample size is toharvest multiple samples in order to obtain sufficient tissue for areliable diagnosis. To do so with the aspiration, core needle biopsydevices or single-action vacuum-assisted devices is only possiblethrough multiple device insertions, resulting in increased patientdiscomfort, time consumption and risk of bleeding.

In the area of breast biopsies, this problem has been solved with thedevelopment of biopsy systems enabling the operator to extract multiplesamples with a single biopsy device insertion. These biopsy devicesgenerally apply vacuum to engage and aspirate a suitable amount oftissue into a hollow portion of the instrument. The power and vacuumsupply units pertaining to those multiple biopsy devices are housed inseparate vacuum stations that require carts for transportation as wellas hoses and leads to function properly. The physical connection betweenthe biopsy device and the accompanying vacuum/power supply units meansthat the freedom of movement of the operator or physician is limited,and auxiliary devices furthermore take up storage and floor space.

In prior art biopsy systems and devices tissue sample extraction,ejection and subsequent storage of the individual tissue samples havebeen accomplished by a number of different methods. Some biopsy devicescomprise mechanical extraction and ejection of extracted tissue samples,as illustrated in U.S. Pat. No. 5,526,822. The biopsy device capturesand holds the tissue sample in a lumen of an inner, rotating cuttingcannula that is retractable to a point outside the anatomy of thepatient. An ejector pin is utilized to push the captured tissue sampleout of the lumen of the cannula.

Other prior art biopsy devices feature vacuum-driven extraction andejection of tissue samples. U.S. Pat. No. 6,638,235 discloses a biopsydevice with an inner, rotating cutting cannula capable of harvestingmultiple tissue samples in a single cannula insertion. The devicereduces operator involvement by enabling the automatic extraction andcollection of multiple tissue samples in a collection chamber placedoutside the anatomy of the patient. Tissue samples are extracted fromthe point of sampling and moved through the inner lumen of the cuttingcannula to the collection chamber by means of a vacuum that is drawnthrough the collection chamber and the inner lumen of the cuttingcannula.

In the sampling, collection and storing of some types of tissue samples,such as prostate tissue samples, it is desirable that extractedindividual tissue cores or samples are kept apart if a subsequentdiagnosis is to be valid.

SUMMARY OF THE INVENTION

It is an object of preferred embodiments of the present invention toprovide a biopsy device and a method that may permit sampling,preferably in an automatic manner. It is a further object of preferredembodiments of the invention to provide a biopsy device, which isconveniently manoeuvrable by a physician. It is a still further objectof preferred embodiments of the invention to provide a biopsy device anda method, which allow for storing of individually separated tissuesamples in a preserving agent. It is a still further object of preferredembodiments of the invention to provide a biopsy device and a method,which allow for convenient penetration of suspect tissue mass. It is astill further object of preferred embodiments of the invention toprovide a biopsy device and a method, which allow for convenientsevering of a tissue sample. It is a still further object of preferredembodiments of the invention to provide a biopsy device and a method,which facilitate handling of acquired tissue samples by a physician.

In a first aspect, the invention provides a biopsy device for harvestingat least one tissue sample from a body of a living being, the devicecomprising:

-   -   a handle unit;    -   a longitudinally extending hollow needle with a distal end        portion adapted to be introduced into the body, the hollow        needle being releasably attached to the handle unit;    -   a sample-receiving device with a cavity for receiving the at        least one severed tissue sample, the sample-receiving device        being receivable in the hollow needle and longitudinally        displaceable therein between a first extended position, in which        the cavity of the sample-receiving device projects from the        distal end portion of the hollow needle, and a second retracted        position, in which the cavity is in a proximal position with        respect to the distal end portion of the hollow needle, and in        which the at least one tissue sample can be ejected from said        cavity;    -   a transport device for moving the sample-receiving device in the        hollow needle between the first extended position and the second        retracted position;    -   a control system for controlling movement of the transport        device and for arresting the sample-receiving device in the        second retracted position.

The second retracted position is normally that position of thesample-receiving device, in which the at least one severed tissue samplemay be ejected from the cavity of the sample-receiving device. In orderto take the burden of arresting the sample-receiving device in thecorrect position off the physician operating the device, theaforementioned control system may thus be configured to automaticallyarrest the sample-receiving device in the second retracted position. Inone embodiment, the control system comprises a sensor for detecting theposition of the sample-receiving device and/or the cavity therein. Forexample, a photocell or an electromechanical switch may be provided forproviding a signal to the control system, when the sample-receivingdevice is in or close to its second retracted position. Alternatively,or in addition, the control system may be arranged to automaticallydetect a distance between the first extended position and the secondretracted position.

It will thus be appreciated that the control system may allow the biopsydevice to automatically operate with different needles of differentlengths, there being no need for configuration by the user of the devicein order to adapt the control system to a specific needle length. Incase the hollow needle and the sample-receiving device are comprised ina disposable unit, which is releasably attached to a handle unit of thedevice, exchange of the hollow needle with another one of differentlength is easily performed. Such exchange is further facilitated thanksto the ability of the control system to arrest the sample-receivingdevice in the second retracted position without specific user inputbeing required for adapting the control system to a specific needlelength, and the biopsy device is further rendered fail-safe with respectto correct positioning of the sample-receiving device in the secondretracted position.

The control system may for example be configured to automatically detecta distance between the first extended position and the second retractedposition of the sample-receiving device upon attachment of thedisposable unit to the handle unit. Accordingly, the control system maybe configured to detect placement or replacement of the disposable unitin the handle unit, e.g. by means of a sensor integrated in the handleunit, and, in response to such detection, initiate the aforementioneddetection of the distance between the two positions.

In order to achieve the detection, the disposable unit may comprise anelectronic memory, and the handle unit may comprise an electronicinterface for deriving information stored in the electronic memory, theelectronic interface being configured to communicate the information tothe control system. It should be understood that the ability ofcommunicating between a disposable unit and further elements of thebiopsy device, e.g. the handle unit, constitutes and independent aspectof the present invention, which may benefit from, but which does notrequire the presence of other features disclosed herein. For example,the unit accommodating the control system may be a hand-held or non-handunit. The electronic memory may e.g. comprise a three of four terminalserial EEPROM, EPROM or ROM containing terminals ground, Vdd, CLK andbi-directional data line, such as a serial EEPROM ATMEL AT24C01. Theinformation stored in the electronic memory may e.g. represent adistance between the first extended and the second retracted position ofthe sample-receiving device, a length of the outer hollow needle and/ora length of the bendable elongate element.

As an alternative or supplement to the electronic memory, the controlsystem may comprise a sensor for detecting when the sample-receivingdevice reaches a proximal extremity of its movement range, the movementrange being preferably predefined. The proximal extremity may forexample be the second retracted position or a position at a predefineddistance from the second retracted position, which predefined distanceis independent of the length of the needle, i.e. which does not changewhen the disposable unit is exchanged. A distal extremity of thesample-receiving device may e.g. be the first extended position. Thesensor for detecting the arrival of the sample-receiving device at theproximal extremity may e.g. detect a change in a physicalcharacteristic, for example the change of electrical current or voltage,magnetic field, or the change of an acoustic, optical or mechanicalparameter. The sensor may comprise a Hall sensor, potentiometer, currentmeasuring device or a mechanical switch.

For example, the transport device may comprise a position or movementsignal generator for generating a position or movement signal to thecontrol system indicative of the longitudinal position or movement ofthe sample-receiving device. In this embodiment, the control system isconfigured to, upon mounting of the hollow needle and thesample-receiving device to the handle unit:

-   -   activate the transport device to retract the sample-receiving        device to its proximal extremity and to record the position or        movement signal in the proximal extremity; and to    -   utilize the recorded position signal as a position reference        point for subsequent arresting of the sample-receiving device in        the second retracted position following tissue harvesting.        Preferably, a driving force is transmitted to the transport        device from a motor, which is controlled by a microcontroller,        the microcontroller receiving the position or movement signal as        an input, in dependency of which input an output for the motor        is generated.

To achieve the desired position control of the sample-receiving device,the control system may comprise at least one pulse-emitting device, suchas a Hall element, for producing pulses in dependency of the movement orposition of the sample-receiving device. The proximal extremity of thesample-receiving device may be defined by a mechanical stop for thesample-receiving device, conferring a change in the production of pulseswhen the sample-receiving device makes contact with the mechanical stop.

In case the transport device receives a driving force from anelectrically driven motor, the sensor may, as an alternative orsupplement to the Hall element, comprise a current or voltage sensor formeasuring motor current passing through the motor. Accordingly, a riseof motor current beyond a predefined threshold value may be used as anindicator that the sample-receiving device has reached its proximalextremity, e.g. a mechanical stop.

The aforementioned position signal generator may comprise apotentiometer, the potentiometer being e.g. arranged at a transmissionaxle for transmitting a driving force to the transport device.

Upon mounting of the disposable unit to the handle unit, the controlsystem may perform an initial run or calibration cycle to move thesample-receiving device to its distal and/or proximal extremity todetermine the length of the needle, the distance between the firstextended and the second retracted position of the sample-receivingdevice or any other value, which may render the control system capableof arresting the sample-receiving device in the second retractedposition. The initial run preferably returns the sample-receiving deviceto a default position, e.g. the first extended position.

The handle unit, the hollow needle, the sample-receiving device, thetransport device and the control system and optionally all othercomponents of the present biopsy device may be comprised in a hand-heldunit.

The biopsy device of the present invention may comprise a liquid supplyunit adapted to comprise a flushing liquid, the liquid supply unit beingoperatively connected to the cavity of the sample-receiving devicethrough a hollow liquid transport member so as to allow tissue sampleejection by liquid flushing.

The liquid supply unit as outlined above allows for cautious handling ofthe at least one harvested tissue sample during the biopsy procedure andsubsequent retrieval of acquired tissue samples to maintain thestructural integrity of suspect tissue and allow an accurate diagnosisto be made. Furthermore, individually extracted tissue cores or samplesmay advantageously be kept apart to enable better diagnosticcapabilities. This is beneficial in respect of most kinds of tissuesamples, such as prostate samples. In addition, liquid flushing to ejectthe at least one tissue sample from the cavity of the sample-receivingdevice allows for automated and rapid biopsy procedures with minimalpatient trauma and minimal manual handling of the harvested tissuesample(s) by physicians.

The flushing liquid is preferably a preserving agent, in which theharvested tissue sample is to be stored following ejection from thecavity of the sample-receiving device. The flushing liquid may e.g.comprise saline or formalin. It will be appreciated that no roughhandling of the body tissue sample, e.g. by forceps, is required inorder to remove the harvested tissue sample from the cavity of thesample-receiving device, as ejection may be caused solely under theaction of the flushing liquid. The cavity may have a substantiallycircular cross-section. Particularly advantageous embodiments of thebiopsy device of the present invention are completely handheld andinclude integral vacuum supply and liquid supply mechanisms as well aspower source, thereby eliminating any need for separate (or external)vacuum, fluid and power sources. Alternatively, the vacuum supply and/orpower source could be arranged externally to the biopsy device andconnected thereto by suitable electrical power conductors and vacuumhoses.

In one embodiment, the biopsy device of the present invention comprisesa closed system for tissue-sample extraction and transportation to avoidleakage of bodily fluids, operator exposure to biohazards andcontamination of extracted tissue samples. This embodiment ensures thatmanual handling of extracted tissue samples is minimized, and possiblehandling damage is consequently minimized.

The hollow needle preferably defines a longitudinally extending annularbody portion, which defines a co-extending longitudinal cavity in thehollow needle, and the cavity in the sample-receiving device may have alateral opening for receiving the at least one tissue sample.

In one embodiment of the present invention, the cutting mechanismcomprises a circumferential cutting edge at the distal end of the hollowneedle as described in more detail below. In order to allow efficienttissue severing by the circumferential cutting edge, thesample-receiving device and the hollow needle are preferably movablerelative to each other, such that the sample-receiving device may be ina projecting position, in which it projects from a distal tip of theneedle, and a retracted position, in which it is accommodated in thehollow needle, and in which the distal end of the device is defined bysaid circumferential cutting edge and possibly a tapered tip of thesample-receiving device.

In order to aspirate or suck body tissue into the cavity of thesample-receiving device, the biopsy device of the present inventionpreferably comprises a vacuum pump for generating a suction effect inthe cavity of the sample-receiving device, the vacuum pump being influid communication with the cavity of the sample-receiving devicethrough a longitudinally extending passage in the sample-receivingdevice and/or through the longitudinally extending passage defined bythe hollow needle. For example, there may be provided one or more vacuumports at the bottom of the sample-receiving device, such as in a wallsection defining a bottom of the cavity in the sample-receiving device,through which vacuum port(s) the cavity is in fluid communication withthe interior of the hollow needle, which in turn is in fluidcommunication with the vacuum pump. Alternatively, there may be providedone or more vacuum ports in a side wall forming a side portion of thecavity in the sample-receiving device, through which vacuum port(s) thecavity may be in fluid communication with the interior of the hollowneedle or with a longitudinally extending passage in thesample-receiving device, the interior of the hollow needle or thepassage in the sample-receiving device being in fluid communication withthe vacuum pump. Preferably, the vacuum pump is only operated in a shortperiod of time each time a tissue sample is to be harvested, i.e.immediately prior to severing of the tissue sample. Control of theoperation of the vacuum pump may e.g. be coupled to control of thecutting mechanism and/or to control of the transport device, so that thevacuum pump is only activated when the sample-receiving device is in itsfirst extended position or within a predefined period of time after thesample-receiving device has arrived at the first extended position, orwithin a predefined period of time before the cutting mechanism isactivated to sever the tissue sample. Alternatively, control of thevacuum pump may be coupled to control of the cutting mechanism, e.g.such that the vacuum pump is activated when the hollow needle isretracted to lay bare the cavity of the sample-receiving device, cf. thebelow description of the firing mechanism for severing the tissuesample, and such that operation of the vacuum pump is deactivated whenthe tissue sample has been severed.

The at least one tissue sample harvested by the biopsy device of thepresent invention is preferably harvested in an automatic manner,extracted from the anatomy of the patient, ejected from thesampling-receiving device and individually placed in a suitable tissuestorage container in a storing and/or preserving agent. Thus, theoperator (or pathologist) is free to concentrate on optimizing tissuesampling and minimizing patient trauma.

In the biopsy device of the present invention, the liquid supply unitmay be operatively connected to the cavity of the sample-receivingdevice when the sample-receiving device is in its second retractedposition, and the liquid supply unit is preferably disconnected from thecavity of the sample-receiving device when the sample-receiving deviceis in its first extended position. The first extended position isnormally the position, in which tissue is collected into the cavity ofthe sample-receiving device as the cutting mechanism severs the tissuesample, i.e. in the first extended position, in which thesample-receiving device with its cavity are in a distal position. Thesecond retracted position is a proximal position, in which the harvestedtissue sample may be ejected from the cavity of the sample-receivingdevice.

Preferably, a pump for pumping the liquid from the liquid supply unit tothe cavity of the sample-receiving device is integral in the biopsydevice. The pump may advantageously comprise a peristaltic pump, whichis relative inexpensive. For example, the peristaltic pump may beincorporated in a handle portion of the device. In one embodiment, theperistaltic pump is releasably attached to a handle portion of thebiopsy device, so that exchange of the liquid supply unit isfacilitated, as the peristaltic pump engages a portion of the hollowliquid transport member (e.g. a plastic or elastomeric hose or tube). Inone embodiment, a clamping mechanism is provided, which firmly holds thehollow liquid transport member in abutment with the peristaltic pump,the clamping mechanism preferably being releasable by hand. As analternative, or in addition to the peristaltic pump, the liquid supplyunit may comprise a syringe-like liquid supply chamber and a plungermovably disposed in the liquid supply chamber. Like the pump, the liquidsupply unit may be releasably secured to the handle unit, so as to allowfor convenient exchange thereof.

The biopsy device of the present invention may comprise a handle unit,which houses or incorporates a power source, such as a battery pack, anda motor for driving the transport device. The handle unit preferablyincorporates no means or elements, which come into physical contact withbody tissue, body fluid or the patient's anatomy during tissueharvesting, so that the handle unit may be re-usable, i.e. usable forseveral biopsy procedures that each may involve extraction of multipletissue samples from a patient. The transport device, the hollow needleand the sample-receiving device, which are parts which are likely orinevitably come into contact with body tissue, body fluid or thepatient's anatomy during tissue harvesting, are preferably comprised ina disposable unit, which is releasably secured to the handle unit. Thedisposable unit is intended to be used for one single biopsy procedureand to be disposed of following harvesting of one or more tissue samplefrom a harvesting site in the patient anatomy. As described in detailbelow, multiple tissue samples may be harvested by means of preferredembodiments of the biopsy device without exchanging the disposable unit,once the outer hollow needle of the disposable unit is in place at theharvesting site.

A flushing chamber may be provided, preferably in the disposable unit,the flushing chamber being adapted for attachment of a sample-collectingcontainer to the biopsy device. Hence, the sample-receiving device ispreferably aligned with the flushing chamber in the second retractedposition, however other layouts are contemplated, in which the harvestedtissue sample is conveyed by means of the flushing liquid from thecavity in the sample-receiving device to flushing chamber and from thereto the sample-collecting container. The sample-collecting container maydefine at least one cavity, and preferably a plurality of cavities forreceiving the harvested tissue sample, whereby one or more cavities maycommunicate with the cavity of the sample-receiving device, when thesample-receiving device is in its second retracted position. Thesample-collecting container is preferably releasably mounted to thedisposable unit. The at least one cavity for receiving the tissue samplemay e.g. comprise a plurality of cavities for receiving individualtissue samples, the sample-collecting container further comprising amovement or rotation mechanism for changing the relative position of thecavities relative to the sample-receiving device, so that differenttissue samples harvested at different times can be flushed into separatecavities. For example, the cavities may be circularly disposed on arotatable disk, rotation of which is controlled by a control system ofthe biopsy device (or biopsy system) to automatically align a subsequentcontainer cavity with the flushing chamber and/or sample-receivingdevice, when a body tissue sample has been ejected into a previouscontainer cavity.

The sample-collecting container, also referred to as the “tissue storagecontainer”, may e.g. have a volume of 10-100 ml, such as 20-30 ml. Theliquid supply unit or liquid container may e.g. have a volume of 5-30ml, such as 5-15 ml, such as approximately 10 ml.

The flushing chamber may be connected to an outlet valve of the fluidsupply unit, which may be pressurized as described. An opening in a wallof the flushing chamber permits liquid to move from the pressurisedliquid supply unit into the flushing chamber. On a side of the flushingchamber, opposite the pressurised liquid supply opening, a drain may beprovided leading to the tissue storage container, where extracted tissuesamples may be individually stored. This drain may be opened and closedby a sliding valve or another suitable closure mechanism.

The flushing liquid impacts and dislodges a tissue sample held in thecavity of the sample-receiving device, the tissue sample being ejectedthrough the cavity of the sample-receiving device. The flushing liquidsubsequently carries the tissue sample through the drain and into thetissue storage container. The flow of flushing liquid into and out ofthe flushing chamber is controllable by operation of the slidable valve.In one embodiment, the slidable valve is operatively connected to avalve spring which ensures that the valve in its default position closesthe opening leading to the pressurised fluid supply as well as the drainleading to the tissue storage container. Alternatively, opening andclosing of the valve may be caused by the transport device for movingthe sample-receiving device in the hollow needle, the transport devicecomprising e.g. a bendable elongate element. Thus, a portion of thetransport device may interact with the valve or with a means for openingand closing the valve. In general, means may be provided, which preventthat flushing liquid is being drawn into the inner lumen of the hollowneedle when vacuum is applied to suck tissue into the cavity of thesample-receiving device.

When the sample-receiving device is moved towards the second retractedposition, the sample-receiving device or the transport device is broughtin contact with the slidable valve. The continued retraction of thesample-receiving device causes the slidable valve to be pushed towardsthe back of the flushing chamber so that the opening leading to theliquid supply unit and the drain leading to the tissue storage containerare both opened. This operation permits fluid to enter the flushingchamber, and the sample to move through the drain into the storagecontainer. During this process, the vale spring is energized withpotential energy by mechanical compression or with electrical energy.After a tissue sample has been flushed out of the sample-receivingdevice, it is once again advanced towards the first extended position,whereby the valve is closed, e.g. by electrical energy or by release ofpotential energy stored in the spring.

The tissue storage container may be substantially circular and comprisea number of separate identifiable chambers, wherein each chamber isadapted to receive a tissue sample. The storage container may comprise amovable part operatively connected to a suitable driver mechanism in adriver unit, e.g. the handle unit, so as to permit the automatic changeof chambers as the biopsy procedure progresses and multiple tissuesamples are harvested. Thus, a single tissue sample is preferablycaptured in each chamber, and the subsequent change of chambers ensuresthat each tissue sample and its associated storage liquid are confinedin the tissue storage container.

Individual tissue samples may subsequently be identified through theirrespective placement in the sample-receiving device, and individualchambers may furthermore be named, coded or otherwise maderecognisable/identifiable. A counter may be included to assist theoperator in keeping track of the number of biopsies taken. In order tofurther automate the biopsy procedure several of all of the chambers ofthe tissue storage container may be partially pre-filled with apreserving agent such as concentrated formalin or another suitablepreserving agent. In this way, the flushing liquid injected into theflushing chamber serves at least two purposes, (1) to carry the tissuesample from the sample-receiving device into the storage container, and(2) to adjust the concentration of the preserving agent in the storagecontainer to a level suitable for the preservation of tissue samples.

In order to facilitate tissue penetration of the sample-receivingdevice, the sample receiving device may comprise or be formed as acannula with a sharpened distal tip. The cannula extends coaxially withthe hollow needle in the hollow needle.

It will be appreciated that the handle unit preferably is embodied as ahand held unit, which accommodates all required power, liquid and vacuumsources as well as possible driving mechanisms for needle andsample-receiving device and firing mechanisms, cf. below. Generally, theentire biopsy device of the present invention, including the hollowneedle, the cutting mechanism, the sample-receiving device, thetransport device, the liquid supply unit and all other structuralelements mentioned herein may be comprised in a hand-held unit.

One alternative embodiment of the vacuum-flush mechanism previouslydescribed employs twin syringe-plunger systems as an alternative to asyringe-plunger system and a vacuum-working fan. The presentvacuum-flush mechanism comprises of twin syringe chambers, each with aplunger slidably disposed in the inner cavity of each chamber.

A first chamber functions as a vacuum supply unit and comprises twoopenings, each fitted with a one-way valve. One valve permits air toenter an inner cavity of the chamber when the plunger pertaining to thischamber is retracted. This valve is in fluid communication with theproximal end of the cutting cannula. When the plunger is retracted, airis drawn out of the inner lumen of the hollow needle and a vacuum iscreated. This vacuum is communicated through the inner lumen of thehollow needle and into the inner cavity or tissue cavity of thesample-receiving device where it engages and aspirates tissue throughthe lateral opening of the sample-receiving device and into the innercavity of the container. Another valve permits air to escape when theplunger is moved forward.

The vacuum supply plunger may be powered by a rack-and-pinion system oranother coupling mechanism housed in the handle unit.

Another unit comprises a pressurised liquid supply unit. It comprises ofa syringe-like chamber and a plunger movably disposed inside saidchamber, and has two openings, each fitted with a one-way valve. Onevalve permits the flushing fluid such as saline, water etc. to enter thecavity defined by the chamber when the plunger pertaining to thischamber is retracted. This valve is connected to a liquid supply with atight connection. The liquid supply may comprise a plastic containerwith relatively soft walls, so that in response to retraction of theplunger, flushing liquid is drawn from the liquid supply unit and intothe inner cavity of the chamber. The walls of the plastic containercollapse inward as the container empties, ensuring that no air gets intothe system. By subsequent forward movement of the plunger, the flushingliquid is ejected from the inner cavity of the chamber and through theoutlet valve into a flush-out chamber.

The pressurised liquid supply plunger is operatively connected to thedriver unit and backward motion may be provided by a suitablepower-transmitting component or coupling means mounted for example onthe shaft of the plunger. The forward motion of the plunger ispreferably powered by a spring that is operatively connected to theshaft of the plunger. When the shaft of the plunger is moved backwards,potential energy is stored in the spring. At a given point, the shaft isreleased, and the potential energy stored in the spring is released tomove the plunger forward and eject the flushing liquid from the chamber.At the end of the biopsy cycle, the plunger shaft is once again engagedby the power-transmitting mechanism, and a new cycle may be initiated.

The transport device (or transport mechanism) may be coupled with thecutting mechanism and a compact driver system featuring all necessarycontrols and mechanics. The vacuum supply unit may either be integratedwith the handle unit or it may be arranged in an external orfreestanding unit. The transport mechanism preferably enables thecollection and removal of multiple tissue samples in a fast, efficientand reliable procedure. The cutting mechanism preferably enables theinstant and efficient severing of tissue samples. This may beaccomplished with rotating cutters of spring-loaded mechanisms, althoughelectro-cautery is also applicable. The handle unit comprises driversthat deliver the necessary actuation forces and motions to the transportand cutting mechanisms. This may e.g. be accomplished through severalmeans, the most common being springs, electric motors or air-powereddrives.

The transport device of the present biopsy device may include anysuitable system for moving the sample-receiving device in the hollowneedle, i.e. any system capable of pulling the sample-receiving devicefrom the first extended position to the second retracted position and ofpushing the sample-receiving device from the second retracted positionto the first extended position. For example, the sample-receiving devicemay be mounted on or connected to a rigid, longitudinally extendingelement such as a metallic cannula coaxially arranged inside the hollowneedle. The rigid element may be forwardly and backwardly movable, e.g.by a linear actuator or by a motor-driven friction wheel or gearwheelengaging the rigid element. Thus, the rigid element may e.g. comprise atoothed rack engaged by a motor-driven gearwheel.

In one presently preferred embodiment, the transport device for movingthe sample-receiving device in the hollow needle comprises a bendableelongate element, such as a steel wire, two or more twisted wires, suchas a Bowden cable or any other flexible or bendable element. Theelongate element is preferably bendable away from the longitudinaldirection of the hollow needle, i.e. laterally bendable, and itpreferably has sufficient stiffness or sufficient support in lateraldirections to prevent the bendable elongate element from flexingoutwardly when the sample-receiving device is to be pushed from thesecond retracted position to the first extended position.

Preferably, a coiling device is provided for coiling up the bendableelongate element, the coiling device being preferably arranged at aproximal end of the device, such as at least proximal of the secondretracted position. In embodiments, in which the bendable elongateelement is comprised in a disposable unit, which is attachable to e.g. ahandle-unit or a stationary unit of the biopsy device, the coilingdevice is preferably integrated in the disposable unit as elaborated inmore detail below.

The bendable elongate element may have a longitudinally extendingportion of circular or non-circular cross section, such as e.g.polygonal cross-section, such as triangular or rectangular. A polygonalcross-section confers the possibility that the bendable elongate elementmay be toothed for engagement by a driving gearwheel. Thus, in oneembodiment, the bendable elongate element comprises a row of regularlyspaced teeth extending substantially perpendicularly to a longitudinalaxis of the elongate element. In this embodiment, the biopsy device mayhave a rotatable gear wheel having a rim with teeth for interacting withthe teeth of the elongate element so as to move the elongate element inthe hollow needle along the longitudinal axis. One or more supports maybe provided for supporting the bendable elongate element in the lateraldirection to avoid flexing thereof, the support(s) comprising e.g. twoopposing wall sections arranged with a mutual clearance corresponding toa thickness of the bendable elongate element, the bendable elongateelement being free to slide in the longitudinal direction between thewall sections. Similarly, the bendable elongate element may slidebetween opposing roller elements.

In order to allow the sample-receiving device to rotate relative to thebendable elongate element, the sample-receiving device may be secured orattached to the bendable elongate element by means of a swivel joint.

From the above discussion, it will be appreciated that the samplereceiving device may have a length, which is substantially shorter thana length of the hollow needle, and that a distal end of the bendableelongate element may be attached to a proximal end of thesample-receiving device, so that the bendable elongate element causesmovement of the sample-receiving device in the hollow needle.

It will also be understood that the biopsy device of the presentinvention may comprise a handle unit with a power source and a motor fordriving the transport device, and that the transport device, the hollowneedle and the sample-receiving device may be comprised in a disposableunit, which is releasably secured to the handle unit. A drivinginterface is preferably provided to transmit a driving force from themotor in the handle unit to the bendable elongate element in thedisposable unit.

The coiling device is likely to be contaminated by body tissue and/orbody fluids during tissue sample harvesting, as the bendable elongatemoves in the hollow needle, the inner wall of which may be in contactwith the tissue sample, when the tissue sample is being moved in thecavity of the sample-receiving device. Thus, the coiling device ispreferably comprised in the disposable unit. Irrespective of whether thecoiling device is comprised in the disposable unit or in other parts ofthe biopsy device, such as in the handle unit, the coiling device mayform a spiral. The spiral may e.g. be formed by at least one wallelement, which is arranged such that contact between coiled-up portionsof the bendable elongate element is prevented to avoid uncontrolledbending or varying dimensions of a coiled bendable elongate element.

Embodiments of the biopsy device of the present invention, which form ahandheld unit, preferably also include the transport device, e.g. thebendable elongate element, in the handheld unit.

Further embodiments and features will become apparent from the belowdescription.

Transfer of samples from the point or position of sampling (orharvesting site) to the point or position of collection (or sampleejection) is preferably carried out by means of a flat, toothed bar,preferably of a polymer material such as polypropylene, to which thesample-receiving device is attached, the sample-receiving device beinge.g. in the form of a canoe-like container to hold tissue samples oncethey have been severed. The sample-receiving device may have aside-facing opening for receiving tissue samples, and may have one orseveral vacuum ports to enable the aspiration of tissue into thesample-receiving device by application of vacuum. Severing of tissuesamples may be carried out by means of a coaxial, piston-like systemcomprising a spring-loaded outer cutting cannula (i.e. the hollowneedle) with a sharpened distal end (i.e. the circumferential cuttingedge) and capable of axial movement, and a an inner guiding cannula witha sharpened tip capable of penetrating tissue as the biopsy device ispositioned in the tissue to be sampled. The inner guiding cannula may benon-movable or movable by the transport device described herein. Theinner cannula may have a side-facing notch (or cavity) enabling tissueto prolapse into the inner lumen of the cannula and into the waitingsample-receiving device. The transport system for the sample-receivingdevice and/or for the severed tissue sample is axially movable withinthe inner lumen of the inner cannula, e.g. to advance and retract thesample-receiving device. Power for driving the transport mechanism maybe delivered by an electric or pneumatic driver unit. Expelling ofsamples from the sample-receiving device and into a suitable transportcontainer may be done by means of liquid or pressurized air at the pointof collection (or ejection).

The bendable elongate element may comprise a flat bar, toothed on oneside, and it may be made from a suitable polymer material such aspolypropylene or Nylon™. The bendable elongate element is movedlongitudinally in the cannula system and enables the transport of tissuesamples from the harvesting site at the distal tip of the biopsy device,e.g. the first extended position of the sample-receiving device, to thepoint of ejection, e.g. the second retracted position of thesample-receiving device. It may fit tightly to the wall of the innercannula to ensure lateral stiffness once it enters the cannula. A cavityon the upper side may enable the application of vacuum to the distal endof the system. The distal point of the cannula system may feature anattachment device to enable the temporary coupling of the cannula withthe suspect tissue mass, e.g. a tumour.

The bendable elongate element (or bar) may be coupled with asample-receiving device with a vacuum gate. This vacuum gate may haveseveral different configurations, depending on the application and thedesign of the expelling (i.e. flushing) chamber. The flat toothed barmay establish a vacuum channel in the cannula. The sample-receivingdevice may receive the tissue during the sampling procedure and hold thesampled tissue on its way from the point of sampling or harvesting tothe point of collection. A filter or grid may be provided to ensure thatno tissue escapes the container.

A coupling mechanism between the toothed bar and the sample-receivingdevice may permit a swiveling motion of the sample-receiving devicerelative to the flat bar as the sample-receiving device is readied foremptying (or ejection), to facilitate the emptying procedure.

The toothed bar may interact with a pinion, allowing the conversion ofrotational motion of the pinion to linear motion of the toothed bar toenable the withdrawal of harvested tissue samples and the positioning ofthe sample-receiving device in the cannula system, i.e. in the outerhollow needle. The pinion may be of metal or a ceramic material toensure longevity.

The motor for driving the sample receiving device or pinion may be anelectric motor. Two batteries and a switch (on/off switch) may beprovided for activating and driving the motor. The motor may bepneumatic, which may render the system MRI-compatible.

The coiling device may comprise a spool-like component placed in thehandle to enable the coiling-up of the toothed bar as it is retracted.Hereby the toothed bar will not protrude far beyond the proximal end ofthe transport mechanism. This is an advantage, in particular when takingbiopsies at deep anatomical depths. Alternatively, the toothed bar canbe bent away form its longitudinal direction.

A guiding wheel may be incorporated to stabilize the flat bar and thesample-receiving device as the assembly is advanced into the cannulasystem.

A driver unit of the biopsy device may comprise the followingcomponents: One or more motors integrated in a suitably designed handle.The motor may generally have two main functions, namely to advance andretract the flat, toothed bar with the sample-receiving device, and tocock and release the firing mechanism when a sample has been readied forcutting. The cocking of the cutting mechanism may result automaticallyonce the system is put into operation, with the retraction, emptying andextension of the sample-receiving device automatically following thefiring of the cutting mechanism. Control of the device may result e.g.from the depressing of a pedal or a selection of buttons. The driverunit may be either electrically or pneumatically driven, and it ispreferably an independent, completely freestanding unit with its ownpower supply, vacuum-source and tissue collection container. It may beconfigured to enable (by selection) one or more of the followingoperation modes: stepwise, semi-automatic or fully automatic.

The vacuum supply and the expelling mechanism may either be integratedparts of a handle housing the driver unit, or they may be placed in anexternal unit. The expelling mechanism (or ejection system) may utilizeair pressure, water flushing or a third means of expelling the tissue.

As an alternative to the toothed bar, a wire, e.g. a steel wire, may beused as a transport mechanism. The steel wire can be a single wire, orit can have two or more twisted wires, with or without a core wire, aprinciple known from the so-called Bowden cables. The Bowden cable maybe coiled up as described above. To enable the functioning of such awire, the spool used to coil up the wire may have a groove in itssurface tailored to the dimensions of the wire, and the spool may besuspended in a tight-fitting housing unit, whereby a channel is formedfor the wire. The use of a stiff wire, in combination with the tailoredchannel, enables the retraction and advancement of the sample-receivingdevice within the guiding cannula.

In a default position of the biopsy device, the flat bar with thesample-receiving device may be maximally extended, and thesample-receiving device may be placed in the distal end of the cuttingsystem. The outer cannula may be maximally extended, covering thetissue-receiving port in the inner cannula as the system is advancedinto the body of the patient.

When a sampling sequence is initiated, the driver unit may be activatedto start cocking of a spring-loaded firing mechanism as described inmore detail below, and the outer cannula may be pulled towards theproximal end of the device, opening the tissue-receiving port. Once theouter cannula has been retracted to open the tissue receiving port, avacuum may be applied to the inner lumen of the inner cannula, suckingtissue into the tissue receiving port and into the sample-receivingdevice.

After the cutting mechanism has been retracted, the sample takingmechanism may release the spring-loaded firing mechanism, rapidlyadvancing the outer cannula to sever the tissue sample. Upon severing ofthe tissue sample, the flat, toothed bar with the sample-receivingdevice may be retracted and carry the biopsy sample towards the point ofcollection (or ejection).

A mechanism at the proximal end of the inner cannula may engage andswivel the sample-receiving device when it exits the inner cannula tofacilitate the expelling (or ejection) of samples. As thesample-receiving device enters the expelling chamber, a stream of liquidmay automatically be released to flush the tissue sample out of thesample-receiving device and into a suitable container. The flushingliquid is preferably saline, possibly containing additives forpreserving the sample or preparing it for examination.

Having completed the expelling cycle, the flat, toothed bar and thesample-receiving device are advanced, and the sample-receiving devicemay be positioned in the distal end of the inner cannula in preparationof a new cycle. On the completion of the sampling sequence, the outercannula may be left in the default position to close the tissuereceiving port in preparation of the removal of the biopsy needle. Thetissue storage container may be detached from the biopsy device and sentto the pathologist for further analysis.

A tip of the sample-receiving device may be conical, and it may beconfigured to serve as a penetration point, tissue-receiving port,sample container and a cutting board.

In the present invention, the outer diameters of biopsy needles may bewithin the range from 0.5 mm to 5.0 mm, such as in the range from 1.2 mmto 3.0 mm. Biopsy needles are typically made of stainless steel, butother materials can be used such as titanium, which is MRI compatible.

In order to accurately control movement of the sample-receiving devicein the hollow needle, the sample-receiving device and the hollow needlemay be shaped, so that relative rotational displacement between thesample-receiving device and the hollow needle in said plane isprevented. For example, the outer cutting cannula or hollow needle maycomprise first orientation means adapted to co-operate with matingsecond orientation means of the sample-receiving device, so as to guideand orient the sample-receiving device in a plane substantiallyperpendicular to the axis of movement of the sample-receiving deviceinside the outer cutting cannula. The orientation means may ensurereliable positioning of a sample ejection aperture of thesample-receiving device in a plane substantially perpendicular to theaxis of movement thereof, so as to support automated ejection ofextracted tissue samples. For example, the oval cutting cannula and thesample-receiving device may have oval profiles, or an inwardprotuberance may be provided on an inner wall of the cutting cannula(outer needle), the protuberance engaging a corresponding groove in thesample-receiving device.

The biopsy device of the present invention may further comprise:

-   -   a first user-operable firing mechanism for causing the hollow        needle and the sample-receiving device to be longitudinally        displaced in a distal direction, so as to penetrate body tissue        at or near the suspect tissue mass;    -   a second user-operable firing mechanism for causing the hollow        needle to be longitudinally displaced in a distal direction from        a first position, in which the sample-receiving device projects        from the distal end of the hollow needle, to a second position,        in which the hollow needle essentially accommodates the cavity        of the sample-receiving device, so as to sever said tissue        sample from remaining body tissue at the harvesting site.

It should be understood that the first user-operable firing mechanism isoptional, i.e. the biopsy device may include only the second firingmechanism. The first firing mechanism may advantageously be incorporatedin a separate module, which may or may not be mounted to the deviceduring assembling thereof.

The first firing mechanism is useful for penetrating a suspect tissuemass, e.g. a tumour, penetration of which may be difficult due to e.g.hardness or due to a loosely supported attachment of the suspect tissuemass to surrounding tissue of the body. The loosely supported attachmentmay cause the suspect tissue mass to displace by pressure from the tipof the biopsy needle and to slide past the suspect tissue mass withoutpenetrating it. It has been found that, by firing the inner and outerneedles substantially simultaneously, preferably at a relatively highspeed, it is possible to contact and penetrate even a loosely supportedtissue mass. Below, the substantially simultaneous firing of the outerneedle and the sample-receiving device will be referred to as a “doubleshot”.

The biopsy device may comprise a control system for the first and seconduser-operable firing mechanisms, the control system being configuredsuch that only one of the firing mechanisms can be activated at a time.The control system may be based on electronic control means, whichprovide a control signal to one or more motor(s) and other elements ofthe firing mechanisms. In order to expedite tissue harvesting, thecontrol system may be configured to automatically activate the secondfiring mechanism after firing of the first firing mechanism, i.e. sothat a tissue sample is automatically severed upon penetration of thesuspect tissue mass.

The first and second firing mechanism may comprise respective energystorage and release mechanisms. The energy to be stored may e.g. beprovided by an electrically driven motor. The energy release mechanismsmay be controlled to substantially instantaneously release the storedenergy to fire the outer hollow needle and the sample-receiving devicesubstantially simultaneously (double shot, first firing mechanism) or tofire the outer hollow needle solely (“single shot”, second firingmechanism). The energy storage means may e.g. comprise springs, such ascompression springs. Thus, the first firing mechanism may comprise afirst compression spring, and the second firing mechanism may comprisesa second compression spring, and the device may further comprise atleast one loading mechanism for loading the first and second springs andfor releasing the springs upon loading thereof. The loading mechanismmay comprise one or more elements for transmitting a displacement of oneor more actuators to the springs. The actuator(s) may e.g. comprise atleast one linear actuator and/or at least motor, the rotational motionof which may be converted into linear displacement of one or bothcompression springs. Such conversion of motion may e.g. be provided viaa gear/rack drive, or via abutment of a member protruding from a surfaceof a rotational wheel with a linearly displaceable member. For mostapplications, the force provided by each of the first and second springsmay be 20-150 N, such as 40-80 N, such as approximately 50 N.

The first firing mechanism may be connected to a needle driving member,which is secured to the hollow needle to transmit the firing force ofthe first spring or other energy storage means to the hollow needle. Thefirst and second firing mechanisms, the hollow needle, thesample-receiving device and the needle driving member are preferablycomprised in a disposable unit, which is releasably attached to thehandle unit. The first spring is preferably connectable to the transportdevice for moving the sample-receiving device in the hollow needle, andthe first spring may further be connected to the needle-driving element.Thereby, the hollow needle and the sample-receiving device may belongitudinally displaced upon release of the first firing mechanism.

A first power-driven element, e.g. a motor, may be provided for drivingthe transport device to move the sample-receiving unit backward andforward in the hollow needle. In order to minimize resistance to thefiring force provided by the first firing mechanism, the loadingmechanism may be configured to, upon loading of the first spring,decouple the transport device from the motor, the transport device beingpreferably movable along with the sample-receiving device in the hollowneedle at firing of the first firing mechanism. In one embodiment,motion of the motor is transmitted to the transport device, comprisinge.g. a bendable elongate element, via a gear drive. That gearwheel ofthe gear drive, which engages the transport device, may be left inengagement with the transport device for stabilization thereof duringfiring of the first firing mechanism. Thus, decoupling of the transportdevice from the motor may be performed at a location, which is closer tothe motor in the transmission chain than the actual location ofengagement between the gear drive and the transport device. Theaforementioned stabilization is particularly useful in embodiments, inwhich the transport device comprises a bendable elongate element.

The first and second firing mechanisms may comprise a common triggerelement and a second power-driven element for moving the triggerelement. The trigger element may e.g. comprise a linearly displaceablemember or a rotational member, such as a gearwheel. The control systemof the biopsy device may be configured such that the first firingmechanism can be loaded and fired during a first movement segment of thetrigger element, and so that the second firing mechanism can be loadedand fired during a second movement segment of the trigger element. Forexample, if the trigger element comprises a linearly displaceable memberhaving a certain stroke, the first movement segment may correspond to apart of the stroke, and the second movement segment may correspond to asecond part of the stroke. Alternatively, if the trigger elementcomprises a rotational element, the first movement segment maycorrespond to rotation of an initial angle of e.g. 90°, and the secondmovement segment may correspond to rotation of a subsequent rotation ofe.g. another 90°.

The transport device and the first and second firing mechanisms mayconveniently be powered or driven by one single motor such an electricalmotor or pneumatic motor. It will thus be appreciated that first andsecond movement segments of the motor may be for loading the first andsecond firing mechanisms, respectively, whereas a further movementsegment, e.g. rotation of another 170° of the trigger element, may befor movement of the sample-receiving device between the first extendedposition and the second retracted position.

It will thus be appreciated that the trigger element may be arrangedwith respect to the firing mechanisms and the transport device such thatmovement thereof in a first direction causes firing of at least one ofthe first and second firing mechanisms, and such that further movementof the trigger element in the first direction causes movement of thetransport device to move the sample-receiving device from the firstextended position to the second retracted position for ejection of aharvested tissue sample. This may e.g. happen during rotation of at most360° of the trigger element, cf. the above example of angular ranges,which accumulate to 350°. Movement or rotation of the trigger element ina second direction, e.g. opposite rotation of opposite lineardisplacement, may cause movement of the transport device to move thesample-receiving device from the second retracted position to the firstextended position for harvesting of a further tissue sample and/or forfiring of a further double shot. The movement of the trigger element inthe second direction may cause resetting of the first and/or secondfiring mechanisms to reset the mechanism(s) for a subsequent cycle ofdouble and or single shots.

The control system of the biopsy device may comprise an electricallyactivated solenoid for causing an impart member of the first firingmechanism to move into a path of movement of the trigger element. Forexample, the trigger element may comprise a rotational wheel having anoutwardly protruding element projecting from a surface thereof. When thesolenoid has not caused the impart member of the first firing mechanismto move into the path of movement of the trigger element, the protrudingelement moves past the first firing mechanism without activating itduring movement of the trigger element. Thus, only the second firingmechanism will be activated. If the solenoid is activated, however, theoutwardly protruding element engages the impart member of the firstfiring mechanism, and movement of the trigger element will load and firethe first firing mechanism, before the second firing mechanism ispossibly loaded and fired. It should be understood that the solenoidmay, alternatively, be arranged to move the trigger element, so that itspath of movement coincides with the impart member of the first firingmechanism.

In case the biopsy device is embodied as a hand-held unit, the first andsecond firing mechanisms may advantageously form part of the hand-heldunit.

In one embodiment, the control system of the biopsy device is configuredto operate the firing mechanisms and the transport device in apredefined cycle. Such a cycle may e.g. comprise the steps of:

-   -   optionally performing a double shot, if an operator of the        device has initiated the double shot by providing a        corresponding input to the control system, e.g. via an interface        in the handle unit;    -   activating a vacuum pump optionally included in the device to        aspirate or sever tissue into the cavity of the sample-receiving        device;    -   performing a single shot to sever the tissue sample and        interrupting vacuum suction prior to or subsequent to severing;    -   moving the sample-receiving device to the second retracted        position;    -   ejecting the tissue sample from the sample-receiving device,        e.g. by liquid flushing as described below;    -   returning the sample-receiving device to the first extended        position.

The control system may e.g. be programmable or pre-programmed to performother cycles, e.g. multiple repetition the steps of:

-   -   performing the single shot;    -   moving the sample-receiving device to the second retracted        position;    -   ejecting the tissue sample from the sample-receiving device; and    -   returning the sample-receiving device to the first extended        position,        so as to harvest a plurality of tissue samples without user        intervention between the individual severing (i.e. single shot)        operations.

In a second, independent aspect, the present invention provides a methodof harvesting at least one biopsy tissue sample from a body of a livingbeing, the method comprising:

-   -   providing a handle unit;    -   providing a longitudinally extending hollow needle with a distal        end portion adapted to be introduced into the body, the hollow        needle being releasably attachable to the handle unit;    -   providing a sample-receiving device with a cavity for receiving        the at least one severed tissue sample, the sample-receiving        device being receivable in the hollow needle and longitudinally        displaceable therein between a first extended position, in which        the cavity of the sample-receiving device projects from the        distal end portion of the hollow needle, and a second retracted        position, in which the cavity is in a proximal position with        respect to the distal end portion of the hollow needle, and in        which the at least one tissue sample can be ejected from said        cavity;    -   attaching the hollow needle with the sample-receiving device to        the handle unit;    -   determining a distance between the first extended position and        the second retracted position of the sample-receiving device;    -   severing the at least one tissue sample when the        sample-receiving device is in the first extended position;    -   displacing the sample-receiving device in the hollow needle        towards the second retracted position;    -   arresting the sample-receiving device in the second retracted        position; and    -   ejecting the at least one tissue sample from the cavity of the        sample-receiving device when the sample-receiving device is        arrested in the second retracted position.

As it has become apparent from the above description of the first aspectof the invention, the steps of determining, displacing and arresting arepreferably controlled by a control system.

In a further independent aspect, the invention also provides adisposable unit for a biopsy device, the biopsy device comprising acontrol system, the disposable unit comprising:

-   -   a longitudinally extending hollow needle with a distal end        portion adapted to be introduced into the body of a living        being;    -   a sample-receiving device with a cavity for receiving the at        least one severed tissue sample, the sample-receiving device        being receivable in the hollow needle and longitudinally        displaceable therein between a first extended position, in which        the cavity of the sample-receiving device projects from the        distal end portion of the hollow needle, and a second retracted        position, in which the cavity is in a proximal position with        respect to the distal end portion of the hollow needle, and in        which the at least one tissue sample can be ejected from said        cavity;    -   a device for providing a signal representative of a distance        between the first and second positions of the sample-receiving        device to said control system.

The signal-providing device may e.g. include an electronic memory, amechanical switch, an optically readable or detectable length indicationor any other suitable means. It is not required that the signal itselfidentifies the distance. For example, the signal may simply provide atype identifier of the hollow needle, from which the control system mayderive the distance between the first and second positions.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described with reference tothe drawings, in which:

FIG. 1 is a general illustration of a biopsy device;

FIG. 2 is an exploded view of an embodiment of the biopsy device;

FIGS. 3-6 illustrate a liquid flushing system in the biopsy device;

FIGS. 7-25 illustrate a first firing mechanism for firing an outerneedle and a sample receiving device of a biopsy device essentiallysimultaneously;

FIG. 26 illustrates a locking mechanism for a gearwheel of the firingmechanisms;

FIGS. 27-31 illustrate a second firing mechanism for firing only theouter needle;

FIGS. 32-35 illustrate a mechanism for moving the sample-receivingdevice in the outer needle;

FIG. 36 is an exploded view of a gear chassis of the biopsy device;

FIGS. 37 and 38 illustrate cycles of a trigger wheel of the first andsecond firing mechanisms;

FIGS. 39 and 40 illustrate an embodiment of a system for determining adistance between two positions of the sample-receiving device.

While the invention is susceptible to various modifications andalternative forms, specific embodiments are shown by way of example inthe drawings and are described in detail herein. It should be understoodhowever, that the invention is not intended to be limited to theparticular forms disclosed.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified schematic illustration of a biopsy deviceincorporating features of the present invention. The device includesbiopsy needle 108 comprising a hollow needle 50, in which there isarranged a longitudinally movable tissue sample-receiving device 52. Thesample-receiving device comprises a tapered distal tip 54 and a cavityor canoe 56 for receiving a tissue sample. The sample-receiving devicecomprises a vacuum port 58, which is in fluid communication with thecanoe 56 to allow tissue to be sucked into the canoe once the canoe isplaced at a suspect site within the body of a living being. Vacuum isprovided by a vacuum pump (not shown). A distal end portion of thehollow needle 50 provides a circumferential cutting edge 60 for severingthe tissue sample sucked into the canoe 56. The device comprises aspring-loaded firing mechanism, which in FIG. 1 is schematicallyillustrated by a spiral spring 62, the firing mechanism being arrangedto displace the hollow needle 50 in a forward (distal) direction tosever the tissue sample sucked into the canoe 56. At a proximal end ofthe device, there is provided a sample flushing chamber 109, from whichthe severed tissue sample in the canoe 56 can be ejected into a samplecontainer 64. More specifically, the sample-receiving device 52 with thecanoe 56 is retracted from a first extended position, in which the canoe56 projects from the distal end of the hollow needle 50 as shown in FIG.1, to a second retracted position, in which the canoe 56 is aligned withupper and lower openings in the sample flushing chamber 109. A flushingliquid, such as saline, is applied to eject the tissue sample from thecanoe 56 into the sample container 64, the flushing liquid beingconveyed from a liquid container 114 via a hollow liquid transportmember or tube 116 by the aid of a peristaltic pump 118.

In order to move the sample-receiving device 52 with the canoe 56between the first extended position shown in FIG. 1 and the secondextracted position, there is provided a transport device comprising abendable elongate element 66 in the form of a bendable bar or wire. Alower surface of the bendable bar or wire is toothed, so that it mayengage a rotatable gear wheel or pinion 68 arranged to longitudinallydisplace the bar or wire 66 to thereby move the sample-receiving device52 backward and forward in the hollow needle 50. A motor 70 is providedto impart a driving force on the gear wheel or pinion 68, and a guidingwheel 72 is provided to stabilize the bendable, flexible bar or wire 66.In order to control the bar or wire 66 when the canoe 56 is retractedfor tissue sample ejection, there is provided a coiling device 74 forthe bar or wire 66.

The biopsy device schematically illustrated in FIG. 1 is operated asfollows: initially, the sample-receiving device 52 and the hollow needle50 are arranged, such that the sample receiving cavity or canoe 56 iscovered by the hollow needle 50, i.e. such that the outer surface of thetapered distal tip 54 of the sample-receiving device 52 forms a tapereddistal continuation of the outer surface of the hollow needle 50. Inthis configuration, the needle 108 is caused to penetrate body tissue ofa patient, for example through manual insertion into the patient's bodyby a physician. Once the needle has penetrated a suspect tissue mass,e.g. a tumour, the hollow needle 50 is retracted to the position shownin FIG. 1, thereby compressing the spring 62 and thus loading the firingmechanism for the hollow needle. Vacuum is then applied through vacuumport 58 to suck tissue into the canoe 56. The firing mechanism for thehollow needle 50 is subsequently released, and the hollow needle 50 isfired forwardly, i.e. in a distal direction, to its initial position, inwhich it covers the canoe 56. This forward firing brings about theresult that the circumferential cutting edge 60 of the hollow needlesevers the tissue sample in the canoe 56. The sample-receiving device 52is then retracted to its second retracted position, in which the canoe56 is aligned with the sample flushing chamber. Movement of thesample-receiving device is caused by rotating the gear wheel 68 in aclockwise direction, the gear wheel 68 engaging the flexible bar or wire66, which in turn is attached to the sample-receiving device 52. In theretracted position of the canoe 56, a flow of flushing liquid is forcedto pass through the sample flushing chamber to eject the tissue samplefrom the canoe into the sample container 64. Once ejection has beencompleted, the flow of flushing liquid is interrupted, and the gearwheel 68 is rotated counter clockwise to cause the flexible bar or wire66 to be displaced in a distal direction, whereby the sample-receivingdevice 52 is pushed back to its first extended position. The abovedescribed cycle including tissue sample harvesting and ejection may thenbe repeated one or more times to obtain several tissue samples withoutretracting the hollow outer needle 50 from the suspect site in the body.

It should be understood that the elements provided at the proximal endof the biopsy device shown in FIG. 1, i.e. the firing mechanismincluding spring 62, gear wheel or pinion 68, motor 70, guiding wheel72, coiling device 74, optionally the sample container 64, sampleflushing chamber 109, liquid container 114, tube 116, pump 118, andvacuum pump (not shown) may be conveniently integrated in a handle unitas elaborated in the below-appended description of embodiments of theinvention.

FIG. 2 is an exploded view of an embodiment of a biopsy device accordingto the present invention. The device comprises a left cover part 100 anda right cover part 102 and, interposed between the cover parts, a gearchassis unit 104 and a disposable unit 106 including a biopsy needle 108and a sample flushing chamber 109. There is further provided a firstfiring mechanism 110 for firing the biopsy needle in a first mode asexplained in detail below. The first firing mechanism 110 forms anintegrated unit, which is optional in the present biopsy device. Thegear chassis unit 104 includes a second firing mechanism 112 for firingthe biopsy needle in a second mode as explained in detail below. Theright cover part 102 is formed to accommodate a flushing system forconveying liquid to the disposable unit 106 in order to eject a bodytissue sample from the sample flushing chamber 109. The flushing systemincludes a liquid container 114, to which there is connected a hollowliquid transport member or tube 116, the tube defining a bent portion117. In order for liquid to be conveyed from the container 114 to thesample flushing chamber 109 through the tube 116, there is provided aperistaltic pump 118 for engaging the bent portion 117 of the tube 116.When mounted in the right cover part 102, the bent tube portion 117 isheld firmly against the peristaltic pump 118 by means of a pair of jaws120, 122. When assembled, the left and right cover parts 100, 102, thegear chassis 104 and the flushing system 114-122 forms a handle unit105, to which the disposable unit 106 is releasably securable. A lockingknob 124 comprising an internal bushing 126 is provided to releasablysecure the disposable unit 106 to the handle unit 105.

The liquid flushing system is disclosed further in FIGS. 3-6. In theexternal surface of right cover part 102, there is provided indentations128, 130 (see FIG. 2) and 132 for receiving the liquid container 114,the peristaltic pump 118 and the tube 116, respectively. A pair ofprojections 134 is provided at upper and lower edge portions ofindentation 128 to secure the container in the indentation 128. Theliquid container 114 and the tube 116 are disposable elements, which anoperator of the biopsy device may exchange on a regular basis. Exchangeof these elements do not require removal of the pump 118, which normallyremains attached to the right cover part 102 during exchange of thecontainer 114 and tube 116. In FIG. 3, the jaws 120, 122 are open, andthe container 114 and the tube 116 are ready to be placed in thecorresponding indentations 128, 130 and 132 formed in the right coverpart 102. FIG. 4 illustrates the container 114 and the tube 116accommodated in the right cover part, with the bent tube portion 117adequately placed around the circumference of the pump 118. In FIG. 4,the jaws 120 and 122 are open, whereas in FIG. 5, the jaws are partiallypivoted to their closed position, and in FIG. 6 the jaws 120, 122 arefully pivoted to their closed position, in which they keep the bent tubeportion 117 in close contact with the pump 118. When the container 114and tube 116 are thus mounted in the right cover 102, the free end oftube 116 is connected to a conduit in the disposable unit 106 (cf. FIG.2) for providing a fluid path from the container 114 to the sampleflushing chamber 109 of the disposable unit.

The first firing mechanism 110 generally illustrated in FIG. 2 will nowbe further described with reference to the exploded view of FIG. 7. Thefiring mechanism 110 is arranged to fire the sample-receiving device 52and the outer needle 50 of the biopsy device substantiallysimultaneously. Referring back to FIG. 1, the sample-receiving device 52and the outer hollow needle 50 may thus be fired substantiallysimultaneously. Such simultaneous firing is useful for penetrating asuspect tissue mass, e.g. a tumour, penetration of which may bedifficult due to e.g. hardness or due to a loosely supported attachmentof the suspect tissue mass to surrounding tissue of the body. Theloosely supported attachment may cause the suspect tissue mass todisplace by pressure from the tip of the biopsy needle and to slide pastthe suspect tissue mass without penetrating it. It has been found that,by firing the inner and outer needles substantially simultaneously at arelatively high speed, it is possible to contact and penetrate even aloosely supported tissue mass. Below, the feature comprisingsubstantially simultaneous firing of the outer needle and thesample-receiving device will be referred to as a “double shot”.

The method of operation of the double shot firing mechanism 110 of FIG.7 will be described below with reference to FIGS. 8-26. The mechanismcomprises a primary axle 136 extending longitudinally through andparallel to a longitudinal axis of compression spring 138 and through aglider 140. A double shot frame 142 supports the spring 138 and theglider 140 between opposing wall sections 144, 146. This is also visiblein FIG. 2, from which it is also apparent that the free end 141 ofglider 140 extends into the disposable unit 106 through opening 107, thefree end 141 engaging a yoke 182 (cf. FIG. 13), which in turn engages aneedle driver 111 fixed to the outer surface of hollow needle 50. Belowthe spring 138, a solenoid 148 extends through the frame, on theopposing side of which the solenoid extends through a nut 150,compression spring 152 and into solenoid holder 154. The solenoid holder154 engages a double shot lever 156 via a solenoid-connector axle 158extending through the lever 156 and into the solenoid holder 154. Anupper pivot pin 160 for the lever 156 is pivotally supported relative tothe frame 142 and extends through frame projection 162, whereby solenoid148 may cause the lever 156 to pivot around pivot pin 160. The doubleshot mechanism 110 further comprises a sliding rail 164, a sliding pawl166, a spring pawl 168, and an impart member 170. Two through-goingpassages are provided in the impart member 170, a first passage 172 forthe solenoid-connector axle 158, and a second passage 174 for theprimary axle 136. An impart member return spring 173 is provided betweenthe impart member 170 and a distally facing surface 143 of the glider140.

FIG. 8 includes structure of the biopsy device, which contributes to thedouble shot, i.e. substantially simultaneous firing of the outer, hollowneedle 50 and the sample-receiving device 52. The double shot firingmechanism 110, illustrated in exploded view in FIG. 7, is assembled andmounted to the gear chassis unit 104 (cf. FIG. 2), the gear chassis unit104 also supporting the disposable unit 106. In FIG. 8, the gear chassisunit is only partially shown for the sake of clarity. A motor-driven,toothed trigger wheel 176 is provided for causing compression of thecompression spring 138 (cf. FIG. 7) as explained below with reference toFIGS. 11-17.

As shown in the end view of FIGS. 9 and 10, the lever 156 has twopositions, an angled position as shown in FIG. 9, and a verticalposition as shown in FIG. 10. The lever 156 is normally biased towardsthe angled position of FIG. 9 by the compression spring 152, thecompression spring 152 being omitted in FIGS. 9 and 10 for the sake ofclarity. In case an operator of the biopsy device intends to fire theouter, hollow needle 50 and the sample-receiving device 52 substantiallysimultaneously, i.e. to perform a double shot, an appropriate input isprovided to an electronic control system of the biopsy device, e.g. viaa keypad on an external surface of the cover 100, 102 (cf. FIG. 2). Thedouble shot action commences by activation of the solenoid 148 to pivotthe lever 156 around the upper pivot pin 160, whereby the lever ispivoted from the angled position of FIG. 9 to the vertical position ofFIG. 10.

Subsequently, as shown in FIG. 11, the trigger wheel 176 is rotated inthe direction of arrow 178. During the course of this rotation, a firstbearing element 180 protruding from a surface of the trigger wheel 176contacts the impart member 170, whereby the impart member 170 isdisplaced in the distal direction along the solenoid-connector axle 158.The stroke of the impart member 170 is defined by sidewalls of thelever. Thus, when the impart member 170 has arrived at the positionshown in FIG. 12, further displacement thereof in the distal directionis not possible. As it will be described in detail below, thisdisplacement of the impart member 170 causes the glider 140 (cf. FIG.7), the needle driver 111 (cf. FIGS. 2 and 8) as well as outer, hollowneedle 50 and the sample-receiving device 52 to be displaced in thedistal direction, while the compression spring 138 is compressed, thethus compressed compression spring 138 being shown in FIG. 12 andomitted in FIG. 11. The firing mechanism for substantial simultaneousfiring of the inner and outer needles is now loaded.

The loaded firing mechanism is illustrated in perspective view in FIG.13. Compression spring 138 is loaded, and a yoke 182 has been moved to aproximal, i.e. retracted position shown in FIG. 13. The yoke 182 isconnected to the glider 140 via a forcing pin 202 (cf. FIG. 18) engagingan indentation formed in the free end 141 of the glider 140, and theyoke 182 engages the needle driver 111, whereby rotation of the triggerwheel 176 in the direction of arrow 178 (cf. FIG. 11) causes the yoke182 as well as the needle driver 111 and the outer needle 50 to beproximally displaced. The outer, hollow needle may thus be moved fromits first extended position shown in FIG. 8 to its second retractedposition of FIG. 13. As further illustrated in FIG. 13, the yoke 182defines a recess 184, in which there is accommodated a slider 186, theslider 186 having an outwardly protruding centre piece 188. Duringretraction of the yoke 182, i.e. during loading of the double shotfiring mechanism, the centre piece 188 is forced downwardly to engagethe bendable elongate element 66, which is secured to thesample-receiving device 52. The required downward movement of the centrepiece 188 is caused, as the centre piece 188, during proximal movementof the yoke engages an engagement member (not shown), which may, e.g.form part of a housing (not shown). Hence, when yoke 182 is moved in aproximal direction, the centre piece 188 is likewise displacedproximally, and in turn the bendable element 66 and the sample-receivingdevice 52 are moved along with the centre piece 188 of slider 186.

In the shown embodiment, the bendable element 66 comprises a toothedflexible wire or flexible rack, which is driven by an advancinggearwheel 190 (cf. FIG. 19) engaging teeth of the toothed flexible wire66. Thus, rotation of the gearwheel 190 may cause the bendable elongateelement 66 and the sample-receiving device 52 to be distally orproximally displaced, depending on the rotational direction of thegearwheel 190. A supporting roll 192 is provided for stabilizing theflexible wire 66, i.e. to prevent it from flexing upwardly, when it ismoved in a distal direction to push the sample-receiving device 52 inthe distal direction.

In one embodiment, the bendable elongate element 66 is made from Nylon6-6. The bendable elongate element may have a generally circular crosssection with flattened upper and lower surfaces, so that the elementforms a wire with flat upper and lower surfaces and arc-shaped right andleft surfaces. For example, the diameter of the element may beapproximately 1.2 mm, with a cross-sectional dimension between theflattened upper and lower surfaces being approximately 0.85 mm. In oneembodiment, the outer needle 50 has an outer diameter of approximately2.1 mm and an inner diameter of approximately 1.8 mm, the outer diameterof the sample-receiving device 52 being, in that embodiment,approximately 1.8 mm, the inner diameter of the sample-receiving devicebeing 1.5 mm.

When the impart member 170 has been moved to its proximal extremityshown in FIGS. 12 and 13, a spring biased release hatch 194 defining acam 196 engages a distally facing edge on the lower surface of theglider 140 as shown in FIG. 14. The release hatch 194 is not visible inFIGS. 11-13, as it is hidden behind the lever 156 and the trigger wheel176. The release hatch 194 is rotationally spring biased, such that thecam 196 slides along the lower surface of the glider 140, until theimpart member 170 and thus the glider 140 have reached their proximalextremity.

At this stage, rotation of the trigger wheel 176 is interrupted, and thesolenoid 148 is deactivated, whereby compression spring 152 (cf. FIG. 7)returns the lever 156 to the inclined position shown in FIG. 9. Inconsequence, the first bearing element 180 (cf. FIGS. 11 and 12) loosescontact with the impart member 170, and the impart member return spring173 forces the impart member 170 back to its initial position, i.e. itsdistal extremity, as shown in FIG. 15. However, as the release hatch 194engages the glider 140 as shown in FIG. 14, the spring 138 is keptloaded, and hence the glider 140, the yoke 182, the needle driver 111,the outer needle 50, the slider 186, the toothed flexible wire 66 andthe sample-receiving device 52 are prevented from moving in the distaldirection. The firing mechanism is now ready to fire, i.e. to releasespring 138 to substantially simultaneously fire the outer needle 50 andthe sample-receiving device 52.

The side elevation views of FIGS. 16 and 17 show the device from a sideopposite to the side viewed in FIGS. 11-15. Thus, the distal end of thedevice is to the left in FIGS. 16 and 17. Rotation of the trigger wheel176 in the direction of arrow 178 (cf. FIG. 11) is now resumed, thetrigger wheel thus rotating counter clockwise in FIGS. 16 and 17. Asecond bearing element 200 attached to the trigger wheel 176 nowcontacts a proximal portion of the release hatch 194, and the releasehatch is thus caused to rotate clockwise in FIGS. 16 and 17 (counterclockwise in FIG. 14). As a result of this rotation, the cam 196 of therelease hatch 194 moves downwardly, whereby its abutment against theglider 140 is released. The compression spring 138 is consequentlyreleased as illustrated in FIG. 17, and the double shot is fired.

In one embodiment of the invention, the compression spring 138 for thedouble shot is compressed by 20-25 mm during loading of the double shotmechanism as described above, corresponding to a 20-25 mm movement ofthe needle 50 and the sample-receiving device. Hence, in thisembodiment, the needle 50 and the sample-receiving device 52 have beendisplaced 20-25 mm in the distal direction between the two positionsshown in FIGS. 16 and 17, respectively.

The disposable unit 106, incorporating several of the elements describedabove in connection with the double shot firing mechanism, will now befurther described with reference to FIGS. 19-26. The disposable unit 106includes a driving gearwheel 204 for the toothed flexible wire 66. Across-shaped driving axle 206 projects from a side surface of thedriving gearwheel 204, the cross-shaped driving axle 206 engaging acorrespondingly shaped member in the gear chassis 104 (cf. FIG. 2). Thegear chassis 104 includes a motor for providing a driving force to thecross-shaped driving axle 206. The driving gearwheel 204 is arranged todrive an first intermediate gearwheel 208, which in turn is arranged todrive a second intermediate gearwheel 209, which drives the advancinggearwheel 190, the advancing gearwheel being arranged coaxially with thesecond intermediate gearwheel 209 in a plane adjacent the plane of thesecond intermediate gearwheel, whereby appropriate engagement portionsare provided at opposing surfaces of the second intermediate gearwheel209 and the advancing gearwheel 190. These engagement portions provide areleasable interconnection, so that, before the double shot is fired,the second intermediate gearwheel 209 is brought out of engagement withthe advancing gearwheel 190. This disengagement is caused by an arm 191forming part of the yoke 182, which consequently moves with the yoke.When the double shot has been fired, the second gear wheel 209 and theadvancing gearwheel 190 return into mutual engagement. A proximalsection 67 of the toothed flexible wire 66 is widened and includes arecess 69 for engagement by a flange portion 189 of the slider 186'scentre piece 188. The housing element 210 shown in FIG. 18 houses ahelical coiling-up groove for accommodating the toothed flexible wire 66when the sample-receiving device 52 is retracted to its second retractedposition, in which the canoe 56 is aligned with the flushing chamber 109(cf. FIG. 2).

In FIGS. 20 and 21, the centre piece 188 of the slider 186 is lifted outof engagement with the widened proximal end portion 67 of the toothedflexible wire 66. In this mutual position of the elements, the toothedflexible wire 66 may be moved by providing a driving force to thecross-shaped driving axle 206 by an appropriate electrical motor (notshown), which advantageously may be integrated in the gear chassis 104.In FIGS. 22 and 23, the yoke 182 has been partly retracted as describedabove with reference to FIGS. 9-13, which has caused the centre piece188 to engage the widened proximal end portion 67 of the toothedflexible wire 66. Upon further retraction of the yoke 182, a first yokearm 183 engages a recess 113 in the needle driver 111, and a second yokearm 187 engages a recess 185 in the slider 186, cf. also the top viewsof FIGS. 24 and 25.

Following the centre piece 188's engagement with the widened portion 67of the toothed flexible wire, but prior to retraction of the needledriver 111 and the toothed flexible wire 66 for loading of the doubleshot firing mechanism (cf. the above description of FIGS. 8-17), thesecond intermediate gearwheel 209 (cf. the above description of FIG. 19)is brought out of engagement with the advancing gearwheel 190 asillustrated in FIGS. 24 and 25, the second intermediate gearwheel 209engaging the advancing gearwheel 190 in FIG. 24 and being out ofengagement in FIG. 25. Accordingly, the driving gear mechanism for theflexible toothed wire 66 causes no resistance to the loading andreleasing of the double shot firing mechanism. In an alternativeembodiment, the advancing gearwheel 190 is kept in engagement with thewire 66 during loading and firing in order to stabilize the wire 66,i.e. to prevent flexing thereof. In such an embodiment, the firstintermediate gearwheel 208 (cf. FIGS. 20-23) may advantageously bedecoupled from the advancing gearwheel 190 in order to reduceresistance.

FIGS. 25 and 26 generally depict a locking mechanism 220 for locking thedriving gearwheel 204 when the needle 50 is loaded for a single shot,cf. the description of FIGS. 27-31 below. As it will be understood,during the single shot, only the outer needle 50 is caused to beretracted and fired, while the position of the bendable elongate element66 and the sample-receiving device 52 are locked or secured, as thelocking mechanism 220 engages the cross-shaped driving axle 206.

The second firing mechanism, which causes the outer needle 50 with itsdistal circumferential cutting edge 60 (cf. FIG. 1) to be fired in thedistal direction to sever a body tissue in the canoe 56 will now befurther described with reference to FIGS. 27-31. It will be understoodthat only the outer needle 50 is fired, the sample-receiving device 52remaining unaffected by firing of the second firing mechanism 112. Thisfiring of the outer needle 50 will be referred to as “single shot”below. The trigger wheel 176 described above with reference to thedouble shot is also used in the single shot. In FIG. 27, the triggerwheel 176 is in the same position as depicted in FIG. 11. If thesolenoid 148 is not activated and the double shot lever 156 is thus inthe position of FIG. 9, rotation of the trigger wheel 176 in thedirection of arrow 178 (cf. FIGS. 11 and 27) does not cause the firstbearing element 180 to contact impart member 170 (cf. FIG. 11), as theimpart member 170 is not in the plane of the bearing element 180.Consequently, the first firing mechanism, i.e. the firing mechanism forthe double shot, is not loaded. The trigger wheel 176 accordinglyrotates freely to the position of FIG. 28. If, alternatively, thesolenoid 148 is activated and the double shot lever 156 is thus in theposition of FIG. 10, rotation of the trigger wheel from the position ofFIG. 27 to the position of FIG. 28 causes loading and of the double shotfiring mechanism as described with reference to FIGS. 10-17. Once thetrigger wheel has arrived to the position of FIG. 28, and the doubleshot firing mechanism has optionally been loaded and fired, a thirdbearing element 300 protruding from a side surface of the trigger wheel176 opposite to the surface visible in FIG. 28 contacts an uprightimpart cam 302 attached to a trigger arm 304, the arm 304 beingpivotally connected to the handle unit 105 (cf. FIG. 2) at a pivot 306.At its upper end, the trigger arm 304 forms a fork 308 engaging antransmission element 310, a proximal end of which abuts a distal end ofthe compression spring 62, and a distal end of which is connected to theneedle driver 111 via a pivotally mounted element 312.

The element 312 is pivotally mounted to a sliding support member 314secured to the compression spring 62, and it is upwardly spring-biasedto the inclined position shown in FIGS. 27 and 28. The sliding supportmember 314 is connected to the trigger arm 304 via a connector 313integral with the transmission element 310. When the double shot firingmechanism is to be loaded as described above in connection with FIGS.7-26, the element 312 is kept in a substantially non-inclined position(not shown) to allow the needle driver 111 to slide past the uppersurface of the element 312, the element 312 being forced into itsnon-inclined position by the yoke 182 (cf. e.g. FIG. 13).

Upon further rotation of the trigger wheel 176, the trigger arm 304 isrotated around its pivot 306, as the third bearing element 300 impartsthe impart cam 302 of the trigger arm 304, cf. FIG. 29. Consequently,the compression spring 62 is compressed, as a proximal end of the springis appropriately supported. It will be appreciated that in the positionof FIG. 29, the outer needle 50 has been retracted, whereby the canoe 56of the sample-receiving device 52 (cf. FIG. 1) is laid bare distal tothe distal end portion of the outer needle 50. The position of FIG. 29thus corresponds to the position of FIG. 1. In this position, vacuum isapplied to the canoe 56 via the vacuum port 58 to suck body tissue intothe canoe 56. In FIG. 30, the trigger wheel 176 has rotated further to aposition, in which the third bearing element 300 looses its engagementwith the impart cam 302 of the trigger arm 304, and the compressionspring 62 is hence unloaded, whereby the needle driver 111 is releasedand shot (i.e. fired) forwardly, i.e. in the distal direction. Thereby,tissue sucked into the canoe 56 (cf. FIG. 1) is severed by thecircumferential cutting edge 60 of the outer needle 50, so that asevered tissue sample is now accommodated in the canoe 56.

The single-shot firing mechanism 112 is further illustrated in theexploded view of FIG. 31. A supporting axle 316 extends through thecompression spring 62 and is supported proximally thereof by a bushing318 and a lock washer 320. A distal end of the supporting axle 316extends through the sliding support member 314, in which it is supportedby a pair of bushings 322. A pivot pin 315 is provided for the pivotableelement 312. To ensure that the trigger arm 304 is biased in theproximal direction, a biasing mechanism 324 is mounted to the triggerarm 304 via a spring element 326, one end of which is fixed inengagement grooves 328 provided on the trigger arm 304. Another,opposite end of the spring element 326 is fixed to a gate element 330forming the impart cam 302 (cf. FIGS. 27-29). A compression spring 336is provided to bias the pivotable element 312 towards an upwardlyinclined position, in which it is in contact with a proximal surface ofthe needle driver 111 (cf. FIGS. 27-30).

As described above with reference to FIGS. 27-31, rotation of thetrigger wheel 176 causes loading and firing of the single-shot firingmechanism for severing a body tissue sample, which is now collected inthe canoe 56 of the sample-receiving device 52 (cf. FIG. 1). Furtherrotation of the trigger wheel 176 causes movement of the bendableelongate element 66 (cf. FIGS. 1 and 19-23) in the proximal direction tomove the canoe 56 from its first extended position, in which it isaccommodated in the distal end portion of the hollow needle 50, to itssecond retracted position, in which it is aligned with the flushingchamber 109 (cf. e.g. FIGS. 27-30) for ejection of the body tissuesample by liquid flushing. This movement of the bendable elongateelement 66 will now be further described with reference to FIGS. 32-36,showing a drive wheel 340, which forms a toothed arc portion 342 and aconnecting portion 344. A free end of the connecting portion 344 ispivotally mounted to a roller 346, which may slide in a curved track 348formed in a carrier plate 350. The drive wheel 340 is rotationallysupported at a centre point 352 of the toothed arc portion 342. It willbe understood from FIG. 36 that the drive wheel 340 is connected to thetrigger wheel 176 via the rotational support at 352, at which the drivewheel 340 is connected to a cam washer 354 forming a notch 356 forengagement with a reduced diameter portion 347 of the roller 346. Thecam washer 354 engages a circular element 358 secured to the triggerwheel 176. During rotation of the trigger wheel 176 from the initialposition shown in FIG. 11 to the position shown in FIG. 30, the notch356 is out of engagement with the roller 346, and accordingly the drivewheel 340 is not rotated. Upon further rotation of the trigger wheel176, the notch 356 of the cam washer 354 engages the roller 346, andthereby the free end of the connecting portion 344 of the drive wheel340 is forced downwardly in the curved track 348. This in turn causesthe drive wheel 340 to rotate around its rotational support at 352,whereby the drive wheel 340 is rotated from the position of FIG. 32 tothe position of FIG. 34.

During the rotation of the drive wheel 340 as described above, thetoothed arc portion 342 of the drive wheel 340 engages a gear drive,which is not shown in FIGS. 32-34. The gear drive, which is partlyvisible in FIG. 36, comprises a first gearwheel 360, which is engaged bythe toothed arc portion 342 of the drive wheel. The first gearwheel 360drives a second gearwheel 362. An axle 364 for the first gearwheel 360is mounted in a first sleeve 366, and an axle 368 for the secondgearwheel 362 extends through a cross-shaped reinforcement member 369and engages a connector 370, which provides a driving force transmissioninterconnection to the driving gearwheel 204 (cf. FIGS. 19-23) includedin the disposable unit 106 (cf. FIGS. 2 and 8). The disposable unit 206also accommodates the bendable elongate element 66 for moving thesample-receiving device 52 in the hollow needle 50 (FIG. 2), theflushing chamber 109, and the coiling device 74 (FIG. 35) for coiling upthe bendable elongate element 66. The driving gearwheel 204, which isomitted in FIG. 35 in order not to cover the coiling device 74, drivesthe intermediated gearwheel 208 and the advancing gearwheel 190, whichin turn engages teeth of the bendable elongate element 66. When thebendable elongate element 66 is moved in the proximal direction toretract the sample-receiving device for ejection of the harvested tissuesample, the bendable elongate element is coiled into the coiling device74 forming a spiral, which allows the bendable elongate element 66 to bewound up and unwound in a controlled manner.

The gear chassis 104 (cf. FIG. 2) includes further elements shown inFIG. 36. A driving motor 372 is provided for driving the trigger wheel176 via a gear drive 374. A further motor 376 is provided for drivingthe peristaltic pump 118 (cf. FIGS. 2-6) for sample ejection by liquidflush via a spindle 377 and gearwheels 378 and 379. A glide bushing 380is provided for the connector 370 to receive the disposable unit 106 inthe handle unit 105 (cf. 2). A vacuum pump 382 is provided for creatingvacuum suction to suck body tissue into the canoe 56 of thesample-receiving device 52 (cf. FIGS. 1 and 2), the vacuum pump 382being in fluid communication with the canoe 56 via appropriate tubes(not shown) and the vacuum port 58.

The cycle of the trigger wheel 176 described above with reference toFIGS. 9-17 and 27-35 regarding double- and single shot, respectively, isdiagrammatically illustrated in FIGS. 37 and 38. FIG. 37 shows the cycleof the movement of the trigger wheel described in relation to FIGS.28-34 and back. From the position of FIG. 28, the trigger wheel rotatesapproximately 290° to the position of FIG. 34. During a first segment ofthe rotation, S-1, corresponding to the rotation of the trigger wheel176 from the position of FIG. 28 to the position of FIG. 29, thecompression spring 62 is compressed. At S-2, the third bearing element300 looses contact with the upright impart cam 302, thereby unloadingthe spring 62. The trigger wheel 176 has now rotated the cam washer 354(cf. FIG. 36) to the position, in which the notch 356 engages the roller346. During a subsequent segment of the rotation, S-3, the trigger wheel176 rotates further to move the drive wheel 340 from the position ofFIG. 32 to the position of FIG. 34 to thereby pull the sample-receivingdevice 52 backwards to its second retracted position, in which the canoe56 is aligned with the flushing chamber 109 for ejection of the severedtissue sample collected in the canoe 56. Rotation of the trigger wheel176 is now reversed, as indicated by block arrows in FIG. 37. Duringthat segment of the reverse rotation, which is denoted S-4 in FIG. 37,the trigger wheel 176 moves the drive wheel 340 back from the positionof FIG. 34 to the position of FIG. 32 to thereby move thesample-receiving device 52 to the distal end portion of the outer needle50, i.e. to the first extended position of the sample-receiving device.At S-5, the sample-receiving device 52 is now at its distal extremity,and the notch 356 of the cam washer 354 (cf. FIG. 36) disengages theroller 346. A final segment of the reverse rotation of the trigger wheel176, S-6, is an idle run, in which the trigger wheel 176 is moved from aposition approximately equal to the position of FIG. 40 to the positionof FIG. 28. Immediately prior to the termination of the S-6 rotation,the third bearing element 300 contacts and passes the impart cam 302,which is biased in the proximal direction by the spring element 326 (cf.FIG. 31). If a further tissue sample is to be severed, the above cyclemay now be repeated.

In FIG. 38, that segment of the rotation of the trigger wheel 176, whichcauses the double shot described above with reference to FIGS. 9-17, isadded to the S-1-S-6 rotation segments shown in FIG. 37. During a firstrotation segment D-1, the trigger wheel 176 is rotated from the positionof FIG. 11 to the position of FIG. 12 to compress the compression spring138 (cf. e.g. FIG. 12). Upon further rotation, D-2, the compressionspring 138 is unloaded to substantially simultaneously fire the outerneedle 50 and the sample-receiving device 52, i.e. to move the triggerwheel from the position of FIG. 16 to the position of FIG. 17. TheS-1-S-6 rotation segments are now performed as described above withreference to FIG. 37. During a final reverse rotation segment, D-3, thetrigger wheel 176 is rotated from a position, which is slightly upstreamof the position depicted in FIG. 12 (the trigger wheel rotatingcounterclockwise in FIG. 12), to the position of FIG. 11. As thesolenoid 148 (cf. FIGS. 9 and 10) is deactivated, so that the doubleshot lever 156 is biased to its inclined position of FIG. 9, the impartmember 170 is not in the plane of the first bearing element 180 (cf.FIGS. 11 and 12), so that bearing element 180 may pass freely to theposition of FIG. 11 without contacting the impart member 170.

In one embodiment of the invention, the control system of the biopsydevice is configured such that a double shot sequence is automaticallyfollowed by a single-shot sequence. In other embodiments, the doubleshot may be activated without incurring a single-shot sequence.

It will be appreciated that the operation of the device, includingactivation of the double- and single-shot sequences described above withreference to FIGS. 9-35, and activation of ejection flushing, may becontrolled by an operator via an appropriate touch-pad system providede.g. on an exterior surface of the handle unit 105 (cf. FIG. 2).

In the embodiment described above with reference to FIGS. 1-38,controlling of the movement of the needle 50 and the sample-receivingdevice 52 is widely based on mechanical means, except for certainelectronically controlled elements, such as the solenoid 148 (cf. e.g.FIGS. 9 and 10), the motor 372, vacuum pump 382 (FIG. 36) and theperistaltic pump 118 for liquid flushing for tissue sample ejection. Itshould, however, be understood that the control system may incorporatefurther electronic elements. For example, the double- and single shotfiring mechanisms may be driven by separate motors, which areelectronically controlled, and loading and firing of the first andsecond mechanisms for single and double shot, respectively, mayincorporate electronically controlled elements for causing appropriateengagement and disengagement of various parts.

FIGS. 39 and 40 illustrate two alternative embodiments of the controlsystem for determining the distance between the first extended positionof the sample-receiving device 52 and its second retracted position,e.g. to provide automatic detection of the length of the outer hollowneedle 50.

The control system uses a microcontroller 400 to constantly monitor therotation of the motor unit 372 of the handle unit 105. Simultaneouslyherewith, the system monitors, by means of an appropriate positionsensor 371 (cf. FIG. 36) the position of one of the transmission axlesthat are part of the gear system translating the movement from the motorunit to the bendable elongate element 66. Thus, the position of thebendable elongate element may be known at all times, and the system mayconfigure itself according to the length of the bendable elongateelement, and thus to the length of the outer needle 50 (cf. e.g. FIG.2).

The embodiment in FIGS. 39 and 40 includes three sensors that areconnected directly to the motor unit 372 in the handle unit 105, andwhich record the rotation of the motor, cf. FIG. 39. These sensors maybe of the Hall sensor type or of a similar type, and their output is fedinto a motor driver unit 402 and a microprocessor 400. When the motorunit 372 is activated and starts rotating, movement is translated fromthe motor to the bendable elongate element 66. As long as the bendableelongate element is free to move within the lumen of the outer hollowneedle 50, a steady stream of pulses are fed from the Hall sensors tothe motor driver 402 and the microprocessor 400. When the bendableelongate element reaches the end of its movement spectrum, it arreststhe motion of the motor 372 and breaks the steady stream of pulses fromthe sensors. This cease of impulses is recorded by the microprocessor400.

As an additional measure, the microprocessor 400 may record the positionof the aforementioned transmission axle. Information about the positionof the transmission axle may be provided by a potentiometer mounted onthe transmission axle. A DC signal obtained from a wiper of thepotentiometer may reflect the instantaneous position of the transmissionaxle and the entire movement spectrum of the bendable elongate element66 corresponding to an angle of rotation of 300 degrees. Since theposition of the axle when the bendable elongate element 66 reaches itssecond retracted position is recorded—and may be found again by means ofthe output from the potentiometer—the microprocessor 400 may reduce thewear on the motor by gradually reducing its speed and stopping itimmediately prior to reaching the position corresponding to the secondretracted position of the bendable elongate element 66.

An alternative or complement to measuring the rotation of the motor 372directly is to measure motor current passing through the motor. Resultsof this measurement may be transmitted to a microcontroller ormicroprocessor wherein a suitable microprocessor program or softwarecomprises a pre-defined current threshold. This measurement of motorcurrent may be done with a sampling A/D converter integrated with themicrocontroller or a corresponding external device. As long as thebendable elongate element 66 is free to move within the lumen of theouter hollow needle 50, the load on the motor is substantially constant,and thus the motor current is also constant. When the load increasesbecause the rod or rack has reached either end of its movement spectrum,the motor current increases. When the current reaches a pre-definedthreshold value, the current change is recorded by a motor driver unitthat is an integrated part of the control system. Simultaneously, themicrocontroller may record the position of the transmission axle.Information about the position of the transmission axle may be providedby a suitable electrical or optical signal derived from e.g. apotentiometer.

A third means of transmitting information about the length of thebendable elongate element 66 to the microcontroller is to use amechanical means, such as a spring-loaded pin that slides into a recessin the bendable elongate element 66 or the sample-receiving device 52.Also optomechanical means may be utilized.

While the present invention has been described with reference to one ormore particular embodiments, those skilled in the art will recognizethat many changes may be made thereto without departing from the spiritand scope of the present invention. Each of these embodiments andobvious variations thereof is contemplated as falling within the spiritand scope of the claimed invention, which is set forth in the followingclaims.

1. A biopsy device for harvesting at least one tissue sample from a bodyof a living being, the device comprising: a handle unit; alongitudinally extending hollow needle with a distal end portion adaptedto be introduced into the body, the hollow needle being releasablyattached to the handle unit; a sample-receiving device with a cavity forreceiving the at least one severed tissue sample, the sample-receivingdevice being receivable in the hollow needle and longitudinallydisplaceable therein between a first extended position, in which thecavity of the sample-receiving device projects from the distal endportion of the hollow needle, and a second retracted position, in whichthe cavity is in a proximal position with respect to the distal endportion of the hollow needle, and in which the at least one tissuesample can be ejected from said cavity; a transport device for movingthe sample-receiving device in the hollow needle between the firstextended position and the second retracted position; a control systemfor controlling movement of the transport device and for arresting thesample-receiving device in the second retracted position; wherein thehollow needle and the sample-receiving device are comprised in adisposable unit, which is releasably attached to the handle unit, andwherein the control system is configured to automatically detect adistance between the first extended position and the second retractedposition of the sample-receiving device.
 2. A biopsy device according toclaim 1, wherein the disposable unit comprises an electronic memory, andwherein the handle unit comprises an electronic interface for derivinginformation stored in said electronic memory, the electronic interfacingbeing configured to communicate said information to the control system.3. A biopsy device according to claim 2, wherein said informationrepresents a distance between the first extended and the secondretracted position of the sample-receiving device.
 4. A biopsy deviceaccording to claim 1, wherein the sample-receiving device has apre-defined range of movement between a distal and a proximal extremity,and wherein the control system comprises a sensor for detecting a changein a physical characteristic when the sample-receiving device reachesits proximal extremity.
 5. A biopsy device according to claim 4, whereinthe transport device comprises a position or movement signal generatorfor generating a position or movement signal to the control systemindicative of the longitudinal position or movement of thesample-receiving device, and wherein the control system is configuredto, upon mounting of the hollow needle and the sample-receiving deviceto the handle unit: activate the transport device to retract thesample-receiving device to its proximal extremity and to record theposition or movement signal in the proximal extremity; and to utilizethe recorded position signal as a position reference point forsubsequent arresting of the sample-receiving device in the secondretracted position following tissue harvesting.
 6. A biopsy deviceaccording to claim 4, wherein the control system comprises at least onepulse-emitting device for producing pulses in dependency of the movementor position of the sample-receiving device, and wherein the proximalextremity of the sample-receiving device is defined by a mechanical stopfor the sample-receiving device, and wherein said physicalcharacteristic is defined by a change in the production of pulses.
 7. Abiopsy device according to claim 6, wherein the pulse-emitting devicecomprises at least one Hall element.
 8. A biopsy device according toclaim 4, wherein the transport device receives a driving force from anelectrically driven motor, and wherein said sensor comprises a currentor voltage sensor for measuring motor current passing through the motor,the proximal extremity being defined by a mechanical stop for thesample-receiving device.
 9. A biopsy device according to claim 5,further comprising a transmission axle for transmitting a driving forceto the transport device, and wherein the position signal generatorcomprises a potentiometer mounted on the transmission axle.
 10. A biopsydevice according to claim 4, wherein the proximal extremity and thesecond retracted position are at different longitudinal positionsrelative to the handle unit.
 11. A biopsy device according to claim 1,wherein the handle unit, the hollow needle, the sample-receiving device,the transport device and the control system are comprised in a hand-heldunit.
 12. A biopsy device according to claim 1, wherein the transportdevice comprises a bendable elongate element.
 13. A biopsy deviceaccording to claim 1, further comprising a liquid supply unit adapted tocomprise a flushing liquid, the liquid supply unit being operativelyconnected to the cavity of the sample-receiving device through a hollowliquid transport member so as to allow tissue sample ejection by liquidflushing.
 14. A biopsy device according to claim 1, further comprising avacuum pump for generating a suction effect in the cavity of thesample-receiving device, the vacuum pump being in fluid communicationwith the cavity of the sample-receiving device through a longitudinallyextending passage in the sample-receiving device.
 15. A biopsy deviceaccording to claim 1, further comprising: a first user-operable firingmechanism for causing the hollow needle and the sample-receiving deviceto be longitudinally displaced in a distal direction, so as to penetratebody tissue at or near the suspect tissue mass; and a seconduser-operable firing mechanism for causing the hollow needle to belongitudinally displaced in a distal direction from a first position, inwhich the sample-receiving device projects from the distal end of thehollow needle, to a second position, in which the hollow needleessentially accommodates the cavity of the sample-receiving device, soas to sever said tissue sample from remaining body tissue at theharvesting site.
 16. A method of harvesting at least one biopsy tissuesample from a body of a living being, the method comprising: providing ahandle unit; providing a longitudinally extending hollow needle with adistal end portion adapted to be introduced into the body, the hollowneedle being releasably attachable to the handle unit; providing asample-receiving device with a cavity for receiving the at least onesevered tissue sample, the sample-receiving device being receivable inthe hollow needle and longitudinally displaceable therein between afirst extended position, in which the cavity of the sample-receivingdevice projects from the distal end portion of the hollow needle, and asecond retracted position, in which the cavity is in a proximal positionwith respect to the distal end portion of the hollow needle, and inwhich the at least one tissue sample can be ejected from said cavity;attaching the hollow needle with the sample-receiving device to thehandle unit; determining a distance between the first extended positionand the second retracted position of the sample-receiving device;severing the at least one tissue sample when the sample-receiving deviceis in the first extended position; displacing the sample-receivingdevice in the hollow needle towards the second retracted position;arresting the sample-receiving device in the second retracted position;and ejecting the at least one tissue sample from the cavity of thesample-receiving device when the sample-receiving device is arrested inthe second retracted position.
 17. A disposable unit for a biopsydevice, the biopsy device comprising a control system, the disposableunit comprising: a longitudinally extending hollow needle with a distalend portion adapted to be introduced into the body of a living being; asample-receiving device with a cavity for receiving the at least onesevered tissue sample, the sample-receiving device being receivable inthe hollow needle and longitudinally displaceable therein between afirst extended position, in which the cavity of the sample-receivingdevice projects from the distal end portion of the hollow needle, and asecond retracted position, in which the cavity is in a proximal positionwith respect to the distal end portion of the hollow needle, and inwhich the at least one tissue sample can be ejected from said cavity;and a device for providing a signal representative of a distance betweenthe first and second positions of the sample-receiving device to saidcontrol system.
 18. (canceled)